I said it was my personal opinion from the outset and that did not mislead anyone. I was basing this upon my own experiences and anecdotally from the scores of people I have spoken to about their own experiences.. I am exercise intolerant and also have post exertional malaise and that has been the situation for decades. I have always had issues two days after any exertion.
I do wonder how many other people do have POTS/EDS and don't know it? I didn't until this recent years. The dysautonomia is greatly underestimated by many people with ME/CFS. Having got my own diagnoses many other people have sought out and managed to get their own.
Having read a lot of diagnostic criteria about both conditions, this information and study results can vary very much depending on the approach to each research study, the goals/aims and who pays the piper. As a scientist myself, I know this very well to be the case. Read a 1000 scientific papers and another 1000 will dispute their claims. I don't have a closed mind, I like to explore all the possibilities and having experienced these things for myself, I feel pretty sure that this will come out more in due course.